Relay for fuel gauges



June 28, 1938. H. M ORTIER I RELAY FOR FUEL GAUGES Filed March 7, 193s v Hnr/ Mari er Patented June28, 1938 I \RE LAY FbKFUEL GAUGEa. M f 7 Henri M'ert'ir, Clichy. Application Marchfl, 1936;::Ser ial zNmi6'i-flz8e i if In France March 11, 1935 3 Claims. (o1. 73*299) The invention relates to improvements in reilays adapted for enabling gauge pressure to be read at a distant point. The present application is in the nature of an improvement on the devices set forth in French Patent No. 761,812 and in French addition Patent No. {133784.

The present invention deals with various means which may be employed for determining the inif V 25 V tial volume of air in the transmitting (motive) chambers of the relays described in the aforesaid French patents. q

In addition to the motive chambers and/or diaphragms the relay mayinclude means for compensating for errors caused. by variations in barometric pressure, such compensating means being particularly useful when the relay is emplayed in connection with airplane gasoline or oil gauges. Suitable, compensating devices are disclosed in' French addition Patent No. 43,784 referred to above, which may consist of one or more air compression chambers interposed between a pair of transmitting diaphragms, and communicating with the pressuregauge, or more particularly set forth in the aforesaid addition patent.

In the case of a motive (transmitting) diaphragm. and a compensating diaphragm, the means employed may consist in opening the connection leading to the manometer to the atmosphere so as to completely fill the chambers with liquid from the tank, then displacing the motive (transmitting) diaphragm'by means of a regulatable stroke pull-rodlfor controlling the amount of initial air before sealing the manometer connection. i

In the case'where'a single diaphragm replaces the motive (transmitting) and compensating dia- V phragms, the means may comprise placing said diaphragm between two casings of which one connects with the tank andthe other with, the

manometer, the position of the diaphragm being determined as above'by operating it by means of a chain or the like.

The first addition patent describes pressure relays in which a diaphragm, by controlling a predetermined volume within a casing,'is thus adapted to transmit a hydraulicorpneumatic pressure 7 to a distant point. 7 The present application involves practical embodiments adapted to permit of determining this original volume. 7

The devices are shown in the accompanying V 1 drawing, wherein:

' nometer.

. liquid, the pressure of which is to be measured,

enters at a and exerts its pressure on the transmitting diaphragm A'and on the compensating diaphragm B; the connection fitting G leading to the manometer being disconnected, said pressure 10 pushes the diaphragm A to position b, and diaphragm'B to position a. At this instant there is no air in the relay and in order to admit a definite volume of air thereto, the pull-rod D is drawn p ,out in the direction of the'arrow until the shoulder E which is adjustable) abuts against the casing F. During this operation the diaphragm B remains applied against the wall in position 0 and the air admitted through fitting G fills the space left by the displacement of diaphragm A. The fitting G need then merely be tightened and the pull-rod D released to permit the liquid pressure coming from a to be transmitted to ma It will be obvious that any suitable anti-friction sealing joint may be employed to prevent leakage of air about the stem of the pull-rod D. V

Fig. 2 shows an embodiment of a relay wherein the application of the principle of predetermined original volumes permits the use of only one diaphragm which replaces the transmitting and compensating diaphragms shown in Fig. 1 and therefore allows the relay to be usedhorizontally without altering the original average "calibration of the gauge when said relay'is used for-gauging very fiat tanks. The relay is composed of two casings, H and I, separated by a diaphragm J; A pull-rod K (of adjustable length) is connected to diaphragm J by a very flexible chain L. The relay is connected to the tank by means of fitting M and to the pressure gauge 0 by means of fitting N. In order to determine the original volume of air required, the tank is filled and the connection fitting N unscrewed. The pressure, of the liquid forces diaphragm J against the inside wall of easing H. The pull-rod K is drawn out to displace the diaphragm which causes air to be drawn in through fitting N. Thereupon the fitting N is tightened and the pull-rod K released so as to place the device in service. The relay is now compensated and the diaphragm resumes its position since the chain L does not impede its movement. There is thus produced an increase in volume the function of which is described in French Patent No. 761,812.

to be placed in communication with pressure from' the tank and the other side is adapted to be placed in communication with the gauge, and means for initially locating the position of the diaphragm preparatory to using the relay; said means comprising means in the connection to the gauge fortemporarily opening the line to atmosphere, and means manually operable from the tank side of the diaphragm for setting the diaphragm.

2. In a-relay of the character described'adapted to be positioned in existing pipe lines intermediate a tank containing fluid whose pressure is to be measured, and a pressure gauge, which includes a chamber communicating with the fluid Whose pressure is to be measured, a second cham ber communicating with the gauge, and a diaphragm separating the two chambers; the'improvement which comprises means for initially setting the diaphragm, manually operable from the tank side of the diaphragm, and a detachable fitting in the line leading to the gauge.

3. A relay as set forth in claim 2 wherein the walls of the diaphragm chambers are comparatively flat, thus permitting compensating for variations in volume without influencing the pressure transmitted to the pressure gauge.

HENRI MoRTIER. 

